Electrochemistry Corrosion Interview Questions & Answers

  1. Question 1. Define An Electro Chemical Cell. Give One Example?

    Answer :

    A cell which converts chemical energy into electrical energy is known as electrochemical cell. Example: Daniel cell , Batteries.

  2. Question 2. What Do You Mean By Redox Reaction?

    Answer :

    Both reduction and oxidation takes place simultaneously in a cell reaction then it is known as redox reaction of an electrochemical cell.

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  4. Question 3. What Is Electrode Potential?

    Answer :

    It is the measure of tendency of a metallic electrode to lose or gain electrons, when it is in contact with its own salt solution. It is denoted as “E”

  5. Question 4. Define An Origin Of Electrode Potential?

    Answer :

    When a metallic electrode is placed in its own salt solution, two types of reaction takes place.

    •  +ve ions may pass into the solution. M → Mn+ + ne- (oxidation)
    • +ve ions from the solution may deposit over the metal. Mn+ + ne-→M (reduction)

    The above reaction takes place in an electrode then it is known as an origin of electrode potential.

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  7. Question 5. Define Oxidation Potential And Reduction Potential?

    Answer :

    Oxidation potential: The tendency of a metallic electrode to lose electrons.

    Reduction potential: The tendency of a metallic electrode to gain electrons.

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  9. Question 6. How An Electrochemical Is Measured? Define Emf Of An Electrochemical Cell?

    Answer :

    It is measured by EMF.: “The difference of potential which causes flow of electrons from one electrode of higher potential to the other electrode of lower electrode potential”.EMF= ER-EL

  10. Question 7. What Are The Applications Of Electrochemical Cell?

    Answer :

    Determination of sparingly soluble salt.,Determination of the valency ion. Determination of standard free energy change and K.
    Potentiometric titrations can be carried out.,Hydrolysis constant can be determined.

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  12. Question 8. Define Electrochemical Series?

    Answer :

    When various types of metallic electrodes are arranged in their increasing order of standard reduction potential on the basis of hydrogen scale is known as emf series.

  13. Question 9. Write The Significance Of Electrochemical Series?

    Answer :

    To calculate the standard emf of the cell.,Relative ease of oxidation or reduction.
    Displacement of one element by the other., Hydrogen displacement behavior. Determination of equilibrium constant (K) for the reaction.

  14. Question 10. Write The Mathematical Form Of Nernst Equation And Give One Application?

    Answer :

    E = Eo + 0.0591/n log [Mn+]

    Application:

    1. It is used to calculate electrode potential of unknown metal.
    2. Corrosion tendency of metals can be predicted.
    3. Applications of emf series.
  15. Question 11. Define Corrosion?

    Answer :

    The gradual destruction of the metal or an alloy surface by the chemical or electrochemical reaction with its environment. (i.e) metal into metal oxide.

  16. Question 12. What Are The Types Of Corrosion?

    Answer :

    1. Chemical corrosion. 
    2. Electrochemical corrosion
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  18. Question 13. What Are The Factors Which Affect Corrosion?

    Answer :

    1. Air and moisture.
    2. Electrolytes in water.
    3. Presence of impurities in metal.
    4. Presence of gases like CO2 and SO2
    5. Differential aeration.
  19. Question 14. Define Chemical Corrosion. What Are The Types Of Chemical Corrosion?

    Answer :

    It is known as dry corrosion. It is due to the local attack of metal surfaces by the atmospheric gases like oxygen,H2S,SO2 , N2, etc.

    3 types.

    1. Oxidation Corrosion.
    2. Corrosion by other gases.
    3. Liquid-metal corrosion.
  20. Question 15. Define An Electrochemical Corrosion. What Are The Types Of Electrochemical Corrosion?

    Answer :

    It occurs due to the existence of separate “anodic” and “cathodic” areas between which current flows through the conducting solution. At anodic area oxidation occurs and anodic part of metal is destroyed.

    1. Galvanic corrosion.
    2. Concentration cell / Differential aeration corrosion.
  21. Question 16. What Are The Differences Between Chemical And Electrochemical Corrosion?

    Answer :

    Chemical corrosion:

    1. It occurs dry state
    2. Local attack to metal by environment
    3. Chemical corrosion is self-controlled
    4. It follows adsorption mechanism
    5. Ex: formation of mild scale on iron surface

    Electrochemical corrosion:

    1. Wet state (i.e) presence in moisture
    2. Large number of cathodic and anodic areas
    3. It is continuous process
    4. It follows electrochemical reaction
    5. Ex: rusting of iron in moisture
  22. Question 17. What Is Bed Worth Rule?

    Answer :

    The ratio of the volume of the oxide formed to the volume of the metal consumed is pilling bed worth rule

  23. Question 18. Bolt And Nut Made Of The Same Metal Is Preferred In Practice . Why?

    Answer :

    Because such a combination will not permit galvanic corrosion to take place.

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  25. Question 19. What Are The Methods Used To Control The Corrosion?

    Answer :

    1. Sacrificial anode method 
    2. Impressed current cathodic method
  26. Question 20. What Is Paint?

    Answer :

    Paint is a mechanical dispersion of one or more finely divided pigments in a medium (thinner + vehicle) .When paint is applied to a metal surface, the thinner evaporates, while the vehicle undergoes slow oxidation forming a pigmented film.

  27. Question 21. Differentiate Electroplating And Electro Less Plating?

    Answer :

    Electroplating:

    • It is carried out by passing current
    • Separate anode is employed
    • Anodic reaction is M  → Mn+ + ne-
    • Thickness of the plating is 1-100μm

    Electroless plating:

    • Used reducing agent
    • Catalytic surface of the substrate acts as an anode
    • Anodic reaction is R → 0 + ne-
    • It has a thickness of 1-100μm
  28. Question 22. Define Electro Plating And Electroless Plating?

    Answer :

    Electro plating:

    It‟s a process in which the coating metal is deposited on the base metal by passing a direct current through an electrolytic solution containing the soluble salt of the coating metal.

    Electro less plating:

    It is a technique of depositing of a noble metal from its salt solution on a catalytically active surface of a base metal by using a suitable reducing agent.